Each day thousands of Americans are victims of cardiac emergencies. Cardiac emergencies typically strike without warning, oftentimes striking people with no history of heart disease. The most common cardiac emergency is sudden cardiac arrest (“SCA”). It is estimated more than 1000 people per day are victims of SCA in the United States alone.
SCA occurs when the heart stops pumping blood. Usually SCA is due to abnormal electrical activity in the heart, resulting in an abnormal rhythm (arrhythmia). One such abnormal rhythm, ventricular fibrillation (VF), is caused by abnormal and very fast electrical activity in the heart. During VF the heart cannot pump blood effectively. Because blood may no longer be pumping effectively during VF, the chances of surviving decreases with time after the onset of the emergency. Brain damage can occur after the brain is deprived of oxygen for four to six minutes.
Applying an electric shock to the patient's heart through the use of a defibrillator treats VF. The shock clears the heart of the abnormal electrical activity (in a process called “defibrillation”) by depolarizing a critical mass of myocardial cells to allow spontaneous organized myocardial depolarization to resume.
Cardiac arrest is a life-threatening medical condition that may be treated with external defibrillation. External defibrillation includes applying electrodes to the patient's chest and delivering an electric shock to the patient to depolarize the patient's heart and restore normal sinus rhythm. The chance a patient's heart can be successfully defibrillated increases significantly if a defibrillation pulse is applied quickly.
In a scenario where a patient on a gurney is being transported through narrow doorways and down stairwells to an ambulance, or the situation where a patient is in an ambulance moving on a road at high speed with patient cables and IV (intravenous) lines running between the patient and other equipment within the ambulance, if the monitoring/therapeutic device is large or the route to the ambulance is particularly difficult, the paramedic might elect to carry the device separately from the gurney to prevent the device falling off the gurney or onto the patient. However, the paramedic is now restricted in his or her ability to detach the device from the gurney due to the number and length of patient cables between the device and the patient. Similar restrictions occur once the patient is loaded into a patient transport vehicle or when the patient is transferred from the ambulance to the emergency department. The number of cables and their similarity in color or dissimilarity in length can all contribute to delays in treating or transferring the patient and can restrict the paramedic's mobility when treating the patient in a confined space. Additionally, delays may be created with cables having become tangled, or even cut, from their previous uses.
The prior art has tried to solve this problem by providing a wireless module that transmits data to a patient monitor, such as the MobiMed offered for Sale by Ortivus. However, this device does not include a defibrillator and does not have the capability to provide any therapeutic functions such as pacing, defibrillation or synchronous cardioversion without attaching another monitor/defibrillator to the patient, which further increases the complexity and ambulance provider cost. Additionally, the Ortivus patient module does not offer replaceable batteries so functionality is severely limited if a reliable source of battery charging is not available, or if the transport time is excessively long. Additionally, the Ortivus device does not offer a display to allow visual monitoring of the waveforms or vital signs if the other module is out of range or obscured.
Another problem arises when hospital personnel want to charge the batteries of the defibrillator/monitor, but don't want to have to place the unit in a docking station in order to charge the batteries. There also arises the issue of patient confidentiality, such as recently raised by the Federal HIPAA (Health Insurance Portability and Accountability Act) regulations, when identical looking patient monitors are accidentally swapped by operators.
Another problem may occur in a situation where two or more sets of associated wireless devices are used in the same general area. This type of problem could occur in a number of different (medical or non-medical) applications. For example, medical device A is comprised of two parts, a patient data acquisition module (AA) and a display module (AD). The two parts communicate with each other via one of many wireless methods. Medical device B is comprised of two similar parts patient data acquisition module (BA) and display module (BD). In the event of a mass casualty incident, where medical personnel are attending to more than one patient, two or more patients may be laying close to each other. Suppose patient X is being attended to by the operator of device A, and a different operator who is using device B is attending to patient Y. Patient X's vital signs are being acquired by acquisition module AA and transmitted to display module AD. Patient Y's vital signs are being acquired by acquisition module BA and transmitted to display module BD. A problem could arise when, in the state of confusion typically existing in a mass casualty incident, the two display modules become switched. In this case, the operator of display module AD could be viewing the vital signs transmitted from Patient X while attending to Patient Y. This could result in inappropriate administration of drugs or other therapy with potentially serious consequences. The acquisition modules could still be associated to the appropriate display modules, and could still be functioning properly, but the operator could be viewing the wrong patient's vital signs.
Other problems with wireless communications include the fact wireless communications methods cannot be visually assessed by the operator prior to failure, such as a broken or damaged cable can. Wireless communications may not be permitted in critical areas, such as an aircraft environment, in military use, or elsewhere. Some wireless communications means have delays between sending a message and getting a response which are too long for therapeutic and other needs. There is a risk of the operator not being able to find a cable when, for instance, a critical therapy has to be administered where the wireless link cannot support it.